Conventionally, in an outdoor unit of a refrigeration cycle apparatus such as an air-conditioning apparatus, for example, a compressor, a heat exchanger, a blower, and the like are housed within a casing. In addition, the outdoor unit of the air-conditioning apparatus is connected via refrigerant pipes to an indoor unit in which a heat exchanger, a blower, and the like are housed. In the air-conditioning apparatus, when the blower is driven, outdoor air is supplied to the heat exchanger, and when the compressor is driven, refrigerant circulates between the indoor unit and the outdoor unit.
An outdoor unit disclosed in Patent Literature 1 has a bottom panel having a rectangular shape, and a plate-like side panel is provided at a position corresponding to a short side of the bottom panel. The side panel forms one side surface of a casing and is provided with valves to which refrigerant pipes extending from the indoor unit side are connected.